Help Please - PJ bass - when tone @ 20% volume cuts completely

Just re-soldered everything on the control plate, and put in a new cap. When I cut the tone down to say, 20% left, volume cuts completely. Bass is a PJ setup.

I played around with the grounding using alligator clips and even swapped out the tone pot for a new one and have the same issue. This happens with the control plate separated from the body but still connected AND when it’s inserted & screwed back on. No change.

I’m under the assumption I don’t need housing wires going from pot-to-pot ( or the input jack) since the copper shielding on the control plate acts as a common ground?

The bridge ground wire + both pickup’s grounds are twisted together and soldered to the back of the tone pot housing.

This is my first attempt at hands-on electronics (not just theory or ideas) so any help is appreciated.

 

thanks for replying! I’ll try your diagram today. The star ground (pickup, pickup, bridge) is soldered to the back of the 2nd volume knob, and the tone cap is on lug 3 & tone pot casing.

Question: looking at your diagram, does the star ground have to share the same solder bead as the tone cap?

 

As soon as things slow down at work I’ll run a resistance test on the pot w\ cap out of circuit.

Yes, I do have a multimeter and have good, open readings on the following:

• Cap (by itself & installed)
• All pot casing & input jack & shielding combinations
• All segments on the white-wire path

Again, no pot-to-pot or input ground wires since the shielding is acting as a ground.

 

correcting myself from earlier: star ground is soldered to the tone pot

 

The picture I uploaded yesterday showed an orange cap, but it stopped working, so now I’m using a ceramic cheapie.

Here we go!

 

Resolved

After looking at the diagram in reply #2 from tonymcbony and comparing about a dozen others (both bass AND guitar) I noticed all of them had the input grounded EVEN if the control plate, or entire pickguard, was shielded.

exhibit A:


so I made the following changes:

 

Yes, thank you. I was stuck on the idea that with everything shielded all components share a common ground. I still don’t fully understand why this worked, I’m just accepting that it did.

 

thank you! I’ve learned a lot these past few weeks

 

Yes, I did successful continuity tests from each component’s “earth” to the shielding (several times when my sanity was at its lowest)

My hunch lines up with what you mentioned, that it was cap related. The first one failed from amateur soldering mistakes and the 2nd cap (ceramic) had been stored in a drawer for 5 years. Even though it tested fine on the multimeter, I just didn’t trust it so I ordered a new one.